Dirofilaria spp. And angiostrongylus vasorum: Current risk of spreading in central and northern europe

In the past few decades, the relevance of Dirofilaria immitis and Dirofilaria repens, causing cardiopulmonary and subcutaneous dirofilariosis in dogs and cats, and of Angiostrongylus vasorum, causing canine angiostrongylosis, has steadily increased in Central and Northern Europe. In this review, a summary of published articles and additional reports dealing with imported or autoch-thonous cases of these parasites is provided for Central (Austria, Czechia, Germany, Hungary, Lux-emburg, Poland, Slovakia, Slovenia, and Switzerland) and Northern (Denmark, Finland, Iceland, Norway, and Sweden) Europe. Research efforts focusing on Dirofilaria spp. and A. vasorum have varied by country, and cross-border studies are few. The housing conditions of dogs, pet move-ments, the spread of competent vectors, and climate change are important factors in the spread of these nematodes. Dogs kept outside overnight are a major factor for the establishment of Dirofilaria spp. However, the establishment of invasive, diurnal, synanthropic, competent mosquito vectors such as Aedes albopictus may also influence the establishment of Dirofilaria spp. The drivers of the spread of A. vasorum remain not fully understood, but it seems to be influenced by habitats shared with wild canids, dog relocation, and possibly climatic changes; its pattern of spreading appears to be similar in different countries. Both Dirofilaria spp. and A. vasorum merit further monitoring and research focus in Europe

Blocking Synthesis of the Variant Surface Glycoprotein Coat in Trypanosoma brucei Leads to an Increase in Macrophage Phagocytosis Due to Reduced Clearance of Surface Coat Antibodies

The extracellular bloodstream form parasite Trypanosoma brucei is supremely adapted to escape the host innate and adaptive immune system. Evasion is mediated through an antigenically variable Variant Surface Glycoprotein (VSG) coat, which is recycled at extraordinarily high rates. Blocking VSG synthesis triggers a precytokinesis arrest where stalled cells persist for days in vitro with superficially intact VSG coats, but are rapidly cleared within hours in mice. We therefore investigated the role of VSG synthesis in trypanosome phagocytosis by activated mouse macrophages. T. brucei normally effectively evades macrophages, and induction of VSG RNAi resulted in little change in phagocytosis of the arrested cells. Halting VSG synthesis resulted in stalled cells which swam directionally rather than tumbling, with a significant increase in swim velocity. This is possibly a consequence of increased rigidity of the cells due to a restricted surface coat in the absence of VSG synthesis. However if VSG RNAi was induced in the presence of anti-VSG221 antibodies, phagocytosis increased significantly. Blocking VSG synthesis resulted in reduced clearance of anti-VSG antibodies from the trypanosome surface, possibly as a consequence of the changed motility. This was particularly marked in cells in the G2/ M cell cycle stage, where the half-life of anti-VSG antibody increased from 39.3 ± 4.2 seconds to 99.2 ± 15.9 seconds after induction of VSG RNAi. The rates of internalisation of bulk surface VSG, or endocytic markers like transferrin, tomato lectin or dextran were not significantly affected by the VSG synthesis block. Efficient elimination of anti-VSG-antibody complexes from the trypanosome cell surface is therefore essential for trypanosome evasion of macrophages. These experiments highlight the essentiality of high rates of VSG recycling for the rapid removal of host opsonins from the parasite surface, and identify this process as a key parasite virulence factor during a chronic infection

Stochastic Radio Channel Model For Advanced Indoor Mobile Communication Systems

A stochastic radio channel model (SRCM) for broadband indoor mobile systems operating at 5.2 and 17 GHz has been derived within the ACTS project AC085 Magic WAND. The SRCM accurately describes the dispersive nature of real radio channels in time, frequency, direction, and polarization. These effects are important for the design and performance evaluation of advanced receiver structures that exploit the inherent channel diversity, e.g., by means of adaptive antennas. The wideband SRCM takes into account all relevant propagation effects observed in real indoor environments. For example, it includes large-scale fluctuations such as transitions where waves are emerging and vanishing as well as the delay drift of the waves. In the paper, the modeling approach adopted for the SRCM is described and illustrated by simulation results. I Introduction A profound knowledge of the radio channel characteristics is a prerequisite for the development of efficient wireless transmission systems. Many ..

HIGH-ROLL RATE EXPERIMENTS ON A DELTA WING IN TRANSONIC FLOW

The following report deals with some of the experimental test setups and recent results from the wind tunnel tests in the transonic wind tunnel of the DLR project called `Aerodynamic Simulation of Unsteady Maneuvers' (AeroSUM). AeroSUM is an interdisciplinary project involving the Institute of Aerodynamics and Flow Technology and the Institute of Flight Research as well as the Transonic Wind Tunnel in Göttingen. The main focus of the project is the numerical simulation of unsteady maneuvres of fighter aircraft. It will be achieved by solving the time dependent Navier-Stokes equations simultaneously with the inertial equations of the motion of the aircraft. For the validation of these methods it is necessary to establish a dynamic data set investigating a wind tunnel model carrying out dynamic movements. States of critical flow, in which e.g. the topologies of flow change, must be investigated as well